Physics 2012 JAMB Past Questions - Question 16: An object of volume 1m³ and mass 2kg is totally immersed in a liquid of density 1kgm-³ .calculate its apparent weight .

Correct Answer

D

Explanation

Upthrust = weight of fluid displaced.But volume of liquid= volume of solid = 1m3 Mass of liquid = volume x density= 1x1 = 1kgweight of liquid displaced = mg

The apparent weight of an object immersed in a fluid is the difference between its actual weight and the buoyant force acting on it. The buoyant force is the force exerted by a fluid on an immersed object and is equal to the weight of the fluid displaced by the object.

First, let's calculate the actual weight of the object:
Weight = Mass × Gravitational acceleration
Weight = 2 kg × 9.81 m/s² (assuming Earth's gravity)
Weight = 19.62 N

Next, we need to calculate the buoyant force. The buoyant force is given by the formula:

Buoyant Force = Density of the fluid × Volume of the object × Gravitational acceleration

In this case, the density of the fluid is 1 kg/m³, and the volume of the object is 1 m³. So:

Buoyant Force = 1 kg/m³ × 1 m³ × 9.81 m/s² = 9.81 N

Now, we can calculate the apparent weight:

Apparent Weight = Actual Weight - Buoyant Force
Apparent Weight = 19.62 N - 9.81 N = 9.81 N

So, the apparent weight of the object when immersed in a liquid of density 1 kg/m³ is 9.81 Newtons.
=1x10=10Ntherefore upthrust = 10Nweight of solid in air = mg = 2x10=20NApparent weight = weight in air - up thrust= 20 - 10 = 10